Portable hardness testing instrument



April 3, 1945. R. P. DEWEY 2,372,662

PORTABLE HABDNESS TESTING INSTRUMENT Filed Apirz, 1942 2 Sheets-smet 1April 3,1945. R, P, bE-WEY Y 2,372,662

PORTAiBLE HARDNESS TESTING INSTRUMENT Filed April 2, 1942 2 Sheets-Sheet2 to the work and Patented Apr. 3,1945

' UNITED STATES .PATENT [OFFICE 2,372,662 i roaranngrsrlinnnss TESTINGRitchie P. Deweyrltockford, ulvll., assignor to 'Barber-Colman Comporation of Illinois pany, Rockford, Ill., a corppuoatioo April 2, 1942,serial No. v$7.328

' (ci. 'z3-s1) 7 Claims.

The-invention relates toa portable instrument for determining thehardness of solid bodies and more particularly to instruments of thetype which measure the depth of penetration of a point pressed into theworkA under av predetermined pressure.

. 1t is to be understood that I do not thereby m- `tend to limit theinvention to the specific form disclosedbut intend to cover allmodifications and alternative constructions. falling within the spiritand scope-of the invention as expressed in the i appended claims. v

The general object is -to providea hardness tester which may be graspedand held convenlently in one hand, which requires only the applicationof hand pressure in testing soft metals and the like, and which isrelatively inexpensive to manufacture yet is reliable and accurate inoperation.

Another object is to which may be applied faces, surfaces of small areaor surfaces within grooves, close t shoulders or in other locationsdimcult of access.

Still another .object is provide a hardness tester to provide `forapproach penetration of the latter -by the indentor point at a constantangle irrespective of the surface contour of the work.

, A further Objectis to provide a hardness tester adapted to be grippedin one hand and having an indicator capable of being read convenientlywhile the instrument is pressed against the work.

'lhe invention also resides in the novel conto rough or irregular suraformy particularly suited for testing soft metals 'I'he drawings showthe improved instrument in such as aluminum, plastics, and other similarmaterials. Most of the operatingparts are arranged compactly in a body 9adapted to be o grasped and held in the users hand and pressed manuallyagainst the surface M of the material to be tested. The instrumentincludes a pointed indentor element or plunger I0 movably mounted on thebody andarranged to be forced into the surface ofthe material byapplication thereto of a predetermined pressure capable of being createdby manual eiort, fifteen pounds being the approximate -pressure employedwhen the instrument'is to be applied to the soft metals. 'I'he degree ofhardness of the material is determined by the depth of penetration ofthe plunger' from a structionl and arrangement of the instrument.

body, the supporting parts therefor, and to the manner of mounting thepenetrating point to en-v able the foregoing objects to be attained.

Other objects and advantages of the invention will become apparent fromthe following detailed -descriptionof the preferred embodimentillustrated in the accompanying drawings,` in which Figure l is aperspective view of a portable hardness testing instrument embodying thefeatures of the invention.

Fig. 2 is a longitudinal sectional view of the mstrument taken in avertical plane substantially on the line 2- 2 ofFig. 1.

Fig. 3 is a` fragmentary sectional view of the instrument taken alongthe line 3- 3 of Fig. 2. Fig; 4 is an enlargedv view partly inlsection,showing the position of the indentor element or sure applied tothe-tool, one co'f the abutments be- 'point with respect toa piece ofmaterial vunder test.

' Figs. 5 and 6 are fragmentary cross-sectional 'l views and Figs. 'land'8 are fragmentary perspective views illustrating specialapplications of the tester.

While the invention is 'susceptible of various modiilcations andalternative constructions, I

'have shown in the drawings and willherein describe in detail thepreferred embodiment, but

' side of the body and providing lower end bearing or' abutmentvsurfaces 6,1, and 8 of small area which contact the surfac'eM at pointsspaced. both longitudinally and transversely of vthe body' 9 and locatedon opposite sides of the line of hand presing disposed immediatelyadjacent and l preferably coincident with the indentor point l0. y

Proferab1y,the body is iste1oogatod in o direc,-

tion parallel to the work surface M and in this instance comprises arigid fr argkae member I4 en' closed in ashell or casing I5 preferablymade in`- sections removably'secured' together as by bolts` I6. Thebody9 is rigid and shaped so that it y may be encircled substantially by theusers hand beneath the body and shown in Fig. l. The palm ofthe handcontacts the opposite side o f with the ngers extending upwardlyalongone side as the body'and the thenar. that is,'that portion of the palmat the base of the thumb, bears on the I or limit position,

' harder materials, therel for movement toward and from the surface ofthe material to be tested with its axis substantially perpendicular tothe longitudinal axis of the instrument body. As herein shown, thesupport for the plunger is provided by the projection it which surroundsand forms a guide for the plunger. comprises a tube having an enlargedupper end I8 screw threaded into the lower end of a bore I9 formed inthe frame block ld with its axis spaced forwardly from the longitudinalcenter of the body. The projecting portion o the member I2 tapersgradually toward its end which donnes the flat bearing surface 5, thelatter being concentric with the point it and of narrow radial width sothat it bears against only a small area ofgthe work. surface. Theplunger It comprises a ylindrical pin and is guided almost to the end ofthe projection I2 in the lower portion o! a stepped axial bore il. Theyupper portion of this bore guides a cylindrical head 2i on the upper endof the plunger which head is engageable with -a shoulder 22 to preventthe plunger from sliding out of the bore.

The plunger point truste-conical in shape having an included angle ofabout 25 degrees and a attenedend surface 4 approximately .005 of aninch in diameter. Apoint of this contour will penetrate plasticsr andsofter metals such as aluminum, its alloys, copper, brass, etc., underan axial pressure of about fteen pounds, the depth of penetration beinginversely proportional to the hardness.

The plunger I is urged outwardly with predetermined pressure by a spring25 acting a pin 26 slidably supported at one end in the bore I1 and atthe other end in an axially alined aperture in a plug 21 threaded intothe upper end of the'passage I9. The spring is interposed between thelower end of the plug and a peripheral ange 28 formed on the pin, saidange engaging the inner end of the projection I2 when shifted to itslimit position under the influence of the Spring. against the pin thepoint projects 3/64 of an inch beyond the abutment surface 6 oi theprojection I2.

In testing va piece of materialv such as a ilat vmetal sheet M, theprojectionl 2 is pressed against the work surface with sulcient force tocause the plunger to overcome the spring 25 and move upwardly from itsnormal or zero position a distance which is determined by the hardnessof the work'material and the adjustment of the spring. Thus, trate thework a substantial distance under the spring pressure and the upwardmotion of the plunger will be correspondingly small. With will be lesspenetration and a. correspondingly greater movement of the plungerincident to pressing the projection I2 against the work.

In the exemplary instrument, the pressure exerted on the plunger by thespring 2,5 canbe adjusted as required for different types of material byscrewing the plug 2l. into or out of the passage I9.4 Such adjustmentsare usually most conveniently made with reference to a known When theplunger II) is pressed upwardly with the latter in its lowermesti*'flange -28 of the plunger actuating pin. The ar- For this purpose, theprojection standard, that is, the instrument is applied to a piece ofmaterial of known hardness and the spring tension is suitably adjustedvto provide the desired reading of the indicator I'I. It will beunderstood, of course, that the adjustments are made only when theinstrument is calibrated and thereafter the setting is maintainedwithout further change'.

In order to provide aquick and accurate indication of the depth ofpenetration of the plunger I0 into the material under test, theindicator II is arranged to' respond directly to the upward movements ofthe plunger vand the associated actuating pin 26. In the instrumentshown, the indicator is a conventional dial type gauge which may begraduated in thousandths of an inch or in arbitrary units of hardness asdesired. The indicator has the usual pointer 3B (Fig. 1) rotatedrelative to a suitable scale S in response to movements of a verticalpin 3l (Fig. 2) projecting from the underside of the indicator.

. For the convenience of the operator,`the indicator is mounted in ahorizontal position at the Afront end nof the casing as shown in Figs. land 2 where it can be easily seen while the instrument is being pressedagainst the material under test. A split ring 32 clamped around the bodyof the indicator and secured to the forward end of the frame I4 as :by abolt 33 holds the indicator rmly in place with the lower end of the pinBI in substantially the same plane as the flange 2B of the plungeractuating pin. Moreover, the pin is alined in substantially parallelrelationship to the actuating pin 25 and plunger so that it canaccurately conform to the movements of those elements.

Movements of ther plunger and actuating pin are transmitted to the pin3l through an amplifying leverage mechanism comprising, in thisinstance, a lever* 34 pivotally supported at one end on the frame I4 asby a pin 35 and having its free end underlying the pin 31.-' The leveris prefery ably `formed from a flat metal strip one end of rangementissuch that the movement of the .;n

for very soft.materials, the tip 5 will penethrough its full range oftravel, that is, iti of an inch is just su'icient to move the pointer3i! completely. around the scale S.

Thus, the indicator actuator has a definite zero or normal positiondetermined by engagement of the flange 28-with the upper end I8 of theenlargedtube end I8. In this position of the pin 26, the indicatorpointer will be in the zero position. Then, by pressing the instrumentagainst a substance too hard to be penetrated by the point 5, thepointer 30 will turn through one full revolution and again be positionedat zero. This affords a convenient way of checking the condition of thepoint to determine whether it has been broken off or damaged. The extentof projection of the plunger beyond the abutment 6 as deter-- guiarposition ofthe pointer 30. The indicator thus reads in terms of thematerial hardness.

In order to obtain uniform accurate readings, the plunger shouldalways'engase the material to be tested at the same angle, preferablywith its longitudinal axis substantially perpendicular to then surfaceof the material. 'Moreoveig any vibration or wobbling of the instrumentwhile the latter is-pressed against vthework will affect the accuracy ofthe measurement. Suchvibration is prevented and the plunger iseiectually guided in erture and thus-removably hold the shaft inassembled relation with the instrument frame. Rigidly secured to theprojecting end of the pin is a transversely disposed foot 43 in the formoi an elongated plate which may have its lower edge ortion shaped asshown in Fig. l to provide th'e two surface engaging areas 1 and 8spaced trans- .versely of the body 9 and longitudinally from theprojection I2. A pin 44 projecting into the foot 43 as shown in Fig. 1sothat the points 'I and 8 will be of comparatively 'small area anddisposedeon opposite sides ofthe central plane.' However.. where thework surface'contacted is 'flat or substantially so, the -bottoxn of thefoot may be ilat as shown lin Fig. 8. Or to adapt the' instrument foruse on pipes or the like, the foot may be forked or otherwise contouredto fit the work surface. If desired, separate feet of diierent contoursmay be provided and used interchangeably in the'instrument dependingon'the character of the work to be tested. It may be desirablev at timestov apply the instrument to surfaces in which the particular area to betested is located in a different plane from the area against which thecontact areas of the foot '43 must be rested. In orderA to maintain theperpendicular relationship between the plunger and the surface underthese conditions, the spacing of the foot from the instrument body maybe adjusted -by insertion ofA one or more washers 46 (Fig. 1) betweenthe collar 45 and the bottom surface of the frame I4. The removablemountaperture 4| between the prongs 42 serves to locate the f oot insubstantially perpendicular relation to the common axial plane of theprojection I2 and shaft 40. A collar 45 rigid with the shaft seatsagainst the bottom of the'frame I4 to hold the foot in fixed relation tothe frame, this relationship being such that the bearing surface 6 of-the member I2 and the surface engaging areas 1 and 8 of the 'foot 43lie in the same plane substantially parallel-Ito the longitudinal axisof the instrument body.

ingof the `pin permits this adjustment to be made with a minimum of'difiiculty.. e

It will 'be observed that when the instrument is applied to the work,the body 9 is rigidly supported and spaced from the work by theprojections I 2 and I3, the former being disposed immediately adjacentthe indentor point.A This not only facilitates gripping and holding ofthe instrument butalsoadds greatly to its versatility.

' Thus, a three point support and a constantap- Thespacing of the threebearingsurfaces or,`

contact areas '6, 1, and 8 eifectually prevents wobbling oftheinstrument either laterally or longitudinally as it is applied to the'material under test. Moreoventle arrangement of the l foot 43 at therear end of the instrument with the contact areas spaced laterallythereof provides a convenient means for guiding the plunger in itsapproach to the surface of the material. For example, in operating theinstrument, the casing is gripped in the hand in the manner shown inFig. 1 but with the front end tilted upwardly at a slight angle and thefoot 43 is firmly pressed against the surface of the material `to betested.

The entire instrument is then rocked forwardly about the points l and 8as a fulcrum until the surface 6 comes into full contact with thesurfaceof the material. Under these conditions, the plunger I0 is forcedinwardly against the action ofthe spring 25 varying distancesdependingupon the hardness of the material.

When the instrument is `appliedy 'to extremely hard material, theplunger may be forced to its inner limit position in which case/theindicator pointer is moved through its full stroke to give a maximumindication. On the other hand, with relatively soft material, thepressure oi the spring 25 may be effective to push the'plungerjoutwardlythrough its maximum stroke which will be appropriately indicated by themovement of the pointer 30 to the other extreme position. Formaterialhaving a degree of hardness intermediate the above limits, the depth ofpenetration Will vary with the hardness. This may be quickly andaccurately read on the indicator,which as stated herein-before, maybecalibrated to readl directly in units of. hardnessif desired.

For' `use on Work of rough or irregular conproach angle are obtained andthe point is always free to penetrate the work to the full depth de-.teri'nned by its Zero position. This" relation always obtainsirrespective of minor irregularities in the work surface. By mountingthepoint coincident one 'of the abutments, and -by making the latter ofcomparatively .small area, the prowise'uneven surfaces may be measurd asillustrated in Fig. 5, in which' case the foot I3 is' lengthened so thatthe 4point 5 enters at right angles to the work surface. l Theinstrument above described is especially useful in measuring thehardness of fabricated structures and those which cannot be movedconveniently. This is Ibecause it may be grasped and held in' one handand because the point 5 is so shaped that it will penetrate asubstantial/ vdistance into the softer metals, plastics, etc., un- Y dera spring pressure which may be overcome bjr-thev relatively small forcecapable of being exerted conveniently by hand to bring the abutment 6against the work. Such substantial penetration is the result of makin-gthe tip 5 quite sharp as shown, so sharp in fact-that it will enter thework under the spring eiect a distance sunlcient to. prevent the pointfrom being shifted laterallyalong the work.

'I'his application isa continuation in part of my co-pendingapplication, Serial No. V378,167, e

led February 10, 1941.

I claim as' my inventionz- 1.v A portable hardness testing instrumentcomprising. in combination, an elongated body, a bearing memberprojecting from thcunderside of the body adjacent one end thereofincluding a foot having contact areas spaced apart toca- 1t is 'desirameto shape the bottom of the' the material when the of the material, anindicator dicating the depth of transversely of the axis of the body andengageable with the surface of the material to be tested to provide afulcrum about which the body may be rocked, a second bearing memberprojecting from the underside of the instrument body intermediate theends of the body, the outer end of said second member engaging thesurface of body of the instrument is rocked into l'substantiallyparallel relationship to the surface thereof, a plunger slidablylsupported by said second member for movement toward and from the surfaceofthe material, spring means exerting a predetermined pressure on saidplunger urging the tip of the plunger into the material to a depthdependent upon the hardness supported at the forward end of theinstrument body for convenient visual observation when the instrument isheld in the hand, and mea-'ns' operatively connecting lsaid plunger withsaid indicator for inpenetration 'of the plunger. 2. A portablehardness'testing instrument coman elongated body havprising,in-combination, ing its intermediate portion shaped to be gripped inthepalm of one hand,'a plurality of laterally spaced projections rigid withand extending from said body and engageable with spaced portions of thesurface of a piece of material to be tested, an indentor elementdisposed closely adjacent and projecting beyond the plane of the,end ofone of said projections and movable relative to said body, saidprojections, when in full contact with the work surface, acting toinsure apredermined relationship between the indentor element and thework surface during entry of the element, spring means acting on saidindentor element and operating to force the tip of the element into thework surface incident to the pressing of the projections against thesame, and an indicator mounted on the forward end of said body forconvenient observation while the body is'held in one hand andoperatively connected to said indentor element to indicate the depth of.penetration of the element.

31A portable hardness testing instrumentl com.V Ijzvrising, incombination, a

body shaped. to be gripped by one hand of the user with the ngersextending beneath the body and with one portion of the palm of said handcontacting one side of the body and the remaining portion at the base ofthe thumb engaging the top of the body, members rigid with andprojectingdownwardly from said'body and space apart so as vto bedisposed i on opposite sides of the fingers 'gripping said body, saidmembers being brought into contact with the work by the application ofpressure by said hand along a line disposed between salitiL members, anVindentor .point yieldably urgi-ii downwardly and movabile upwardlyrelative to said body and members as aniricident to pressing the latteragainst the work, and mechanism carried by said body and operativelyconnected to said indentor point, said mechanism including an indicatorfor registering the extent of such relative movement.

4. A portable hardness prising, in combination, gripped by one hand ofthe user with the palm of said hand vcontacting one side of the body andthe yfingers extending beneathl the body, membersrigid with and spacedapart longitudinally of said body and extending downwardly from thebody, said members being brought into contact with the work by theapplication of hand pressure in a downward direction and being of atesting instrument coni-` and be moved upwardly relative to said bodyand members as an incidentto pressing the latter against the work, andmechanism carried by said body land operatively connected to saidindentor point, said mechanism including an indicator for registeringthe extent of such relative movement and penetration.

5. A portable hardness testing instrument comprising, in combination, abody shaped to =be gripped by one hand of the 'user and to be pressedmanually against a work surface, a projection rigid with and extendingdownwardly from said body for bearing engagement with a work surface, anindentor point slidably guided in and laterally supported by saidprojection adjacent the end of the latter and yieldably urged downwardlybeyond said end so as to penetrate thework when the projection ispressed against the latter, a second projection rigid with andprojecting downwardly from said body and spaced from said rst mentionedprojectionxtoprovide a space intervening between the two projections,said second projection being adapted when Ipres'sed against the work todenne an axis about which said body may be rocked toward the work tobring the other projection into contact therewith and cause saidindentor point to enter the work at a predetermined angle, and mechanismcarried by said body and operatively connected to said indentor point,said mechanism including an indicator for registering the extent of suchrelative movement.

6. A portable hardness measuring instrument having, in combination, ahollow casing adapted to'be grasped in and partially encircled by onehand whereby to be pressed bodily toward a work surface by handpressure, means rigid with and projecting from said casing near one endthereof providing two abutments engageable with a work surface anddefining an axis about which the other end of the casing may be rockedtoward the work, a projection spaced from said abutments toward theother end of the casing and extending rigidly from the casing to proabody shaped to be y l 'vide an abutment engageable with a small area ofthe work whereby said three abutments support said casing rigidly fromthe work, -a plunger guided for endwise movement by saidprojection andextending beyond said third abutment, means within said casing urgingsaid plunger outwardly to a predetermined position with a predeterminedforce of a magnitude capable"of being overcome by the'application ofhand pressure to said casing, an indentor point on the projecting end ofsaid plunger adapted fto penetrate soft metals under said force, and anindicator carried by said casing and actuated by movement of saidplunger, said indicatorahaving a. movable element adapted to occupy azero position `when said plunger is in said'predetermined position and,movablel away from said position a. distance determined by the amountthat vsaid indentork point penetrates the work when all of` saidabutments are in contact with the latter.

7. A portable hardness measuring instrument comprising, incombinations.- body, an indentor point projecting from the body toengage a Work surface and yieldably urged away from the body,

a plurality of projections rigid4 with and extend--v ingfrom one side ofsaidv body and adapted to bear against said work surface at laterallyspaced eating means connected to said point and operable to register thedepth of work penetrated bysaid point when the body is pressed towardthe work surface and supported through said bearing RI'IVCHIE P. DEWEY.

5 points.

